With the progressive development of the liquid crystal display technology and the price advantage of the liquid crystal display screen, the liquid crystal display screen is used as a display screen of various electronic apparatus in our lives or a decorative electronic display device, which has gradually become a trend of the liquid crystal display screen. The liquid crystal display screen in the prior art has been widely used in various kinds of electric appliances, e.g. a liquid crystal display television, a mobile telephone and so on.
When a specific display picture is displayed on the liquid crystal display screen, a greenish phenomenon (i.e., Greenish (green flickering) phenomenon) may occur. FIG. 1 illustrates a timing diagram of voltage signals applied to the data lines of red, green and blue pixels in the prior art. As can be seen from FIG. 1, the timing graphics of voltage signals applied to data line for pixels of the three colors are exactly the same, that is, the pulse widths at high level of voltage signals applied to data lines for pixels of the three colors are exactly the same. Due to characteristics of the green pixel itself and the special sensing characteristics to green of the human eyes, the human eyes are more sensitive to green light than red light and blue light. When an all white picture is displayed on the display screen, the flicker phenomenon is easy to occur, especially at the instant when the all white picture is switched to a all black picture, the Greenish phenomenon is easier to occur, and when the flicker phenomenon and the Greenish phenomenon occur, green light perceived by the human eyes are more intense.
In the prior art, as shown in FIG. 1, in the case that pulse widths at high level of data line voltage signals applied to data lines for red, green and blue pixels in the display panel are exactly the same, because of the above reasons, Greenish phenomenon will inevitably occur in the picture seen with the human eye. FIG. 2 illustrates a macro-effect diagram locally showing the picture corresponding to the timing diagram of data line voltage signals for pixels of the three colors shown in FIG. 1. Density of black dots and corresponding numbers in FIG. 2 denote the severity of Greenish phenomenon, wherein, the larger the density of black dots is and the bigger the corresponding number is, the higher the severity of Greenish phenomenon is. FIG. 3 illustrates a schematic view of the circuit arrangement applying timing change to data line voltage signals for pixels of the above three colors in the prior art. FIG. 4 illustrates a timing diagram of data line voltage signals applied to pixels of the above three colors under a single clock signal control in the circuit illustrated in FIG. 3.
From the point of structure of the display panel, reasons for Greenish phenomenon inevitably occurring further include: as for a general display picture, during performing wiring on a printed circuit board, the common voltage Vcom wiring may not be centered, which will induce an instable Vcom and result in the fact that changes in the Vcom brought by data line voltage signals cannot be cancelled out, thus brightness of the green pixel is increased, which will in turn result in occurrence of Greenish phenomenon.
In the prior art, methods for solving Greenish phenomenon include: increasing area of Vcom wiring to decrease resistance in the circuit and then enable the Vcom to be stable; or, employing a Matrix Vcom (matrix common voltage) arrangement to change a former pattern, in which a common electrode at the leftmost end is used to connect a plurality of parallel Vcom lines, into a grid pattern, so as to effectively stabilize the Vcom. In the two methods described above, Greenish phenomenon is alleviated by changing the wiring on the printed circuit board, however, occurrence of Greenish phenomenon can not be solved from the fundamental reasons, and moreover, with the technical solutions in the above two methods, aperture ratio of the liquid crystal display screen could be decreased, causing increased power consumption of the screen.